The Study On The Heterosis And The Correlation In The F₂ Generation Of The Main Parents CN18 And CN19

Two main parents R25 and R88 intercrossed with 16 noth high-selfcrossed linesrespectively according to NCâ…¡mating design, to get F₁ hybrids generation, and then getF₂ generation by selfcrossing. The major agronomic characters and quality characters wereanalyzed using F₂ hybrids generation, and we also discussed the difference and thedifferent usage of the two main parents. The following are the results.There was obvious positive heterosis in most characters of the F₂ genation, and theheterosis effect was various in different characters. There were 32 combinations in total. 27combinations had the positive MP heterosis on plant height, including 21 high parent(HP)heterosis combinations; 10 middle parent(MP) heterosis combinations on spike length,including 3 HP heterosis combinations; 22 MP heterosis combinations on tillers, including15 HP heterosis combinations. 11 MP heterosis combinations on spikelet number,including 8 HP heterosis combinations; 12 HP heterosis combinations on grain setting rate,including 6 HP heterosis combinations. There was no heterosis combination on 100-grainweight. Only two combinations on dry, wet gluten content had MP heterosis respectively,but no HP heterosis combination; There was no MP, HP heterosis combination onsedimentation value. 9 combinations had MP heterosis on gluten index, including 4 HPheterosis combinations. It is difficult to get heterosis on quality characters in F₂ genations,but strong heterosis on most other importment characters were showed in this experiment.Optimizing some characters, the F₂ generation will be used in mass production possiblely,for their remarkable heterosis.The comparison of the two group of F₂ generatios hybrided by R25 and R88respectively indicated that: the combinations producted by R88 were remarkably more thanthat producted by R25 on spike length, tillers, spikelet number, grain setting rate, and theinheritance ability of R25 was stronger than R88 on those characters.The correlation analysis between genetic distance based on SSR and heterosisindicated that: the correlation coefficient between GD and HP heterosis on phant heightgroup was negative significant; and it was positive significant between GD and averagevalue, HP, MP heterosis on spikelet number in R88; the correlation coefficient between GD and heterosis on the other characters were not significant in both groups, and it ishard to forcast the heterosis by the GD based on SSR in this experiment.The correlation analysis between the heterosis of the characters indicated that: thecorrelation coefficient between average value on plant height and tillers was positivesignificant. In R25 group, the correlation coefficients between HP, MP heterosis on dry,wet gluten content were both highly significant. It is apt to produce both high dry, wetgluten content progeny utilizing R25 as a parent. In R88 group, the correlation coefficientsbetween gluten index and dry gluten content on average,HP and MP heterosis were greatlypositive significant, but not between gluten index and wet gluten content, sedimentationvalue. We can get high gluten index, dry, wet gluten content by using R88 and suitablechoosing other parent.